Spring for railroad-cars



W. DUFF.

Carriage-Spring.

No. 1.928. Patented Jan. 9, 1841.

AM. PHUTO-LITHO. C0- N-Y (USBDRNES PROCESS) UNITED STATES PATENT OFFICE.

WILLIAM DUFF, OF BALTIMORE, MARYLAND.

SPRING FOR RAILROAD-CARS, LOCOMOTIVES, AND OTHER VEHICLES.

Specification of Letters Patent No. 1,928, dated January .9, 1840.

To all whom it may concern Be it known that I, IVILLIAM DUFF, of thecity of Baltimore, in the State of Maryland, civil engineer, haveinvented certain Improvements in Springs for Railroad-Cars, Locomotives,and other Vehicles; and I do hereby declare that the following is a fulland exact description thereof.

My invention consists in the particular manner in which I have combinedand arranged the elastic spring made of steel plates, with any desirednumber of spiral springs, by which arrangement I attain a high degree ofelasticity, and graduate the actions of the spring in accordance withthe varying burden which it is to sustain.

In the accompanying drawing, I have represented two modifications of myspring; in one of which the elastic force of the spring is made to bearon the under side of the main frame alone; and in the other, the spiralsprings are made to act above the main frame, between it and the frameof a car body, or other weight.

A, A, is one side of the main truck, car, or locomotive frame, and A, B,a steel spring which may consist of two, or more, plates, one placedupon the other, and combined in the ordinary way. The upper plate ofthese springs I usually bend around so as to form a scroll at each end,and through the middle of these scrolls I pass the bolts a, a. Thestraps C, C, in this case, I make fast to the frame, as the scrolls atthe ends will, by their unwinding and winding, admit of the necessaryelongation and contraction of the steel plate. The straps C, C, may,however, be made to swing, in the ordinary way, or the ends of thesprings may be received within pockets.

D, D, D, are spiral springs of steel, which are coiled around rods ofmetal, the lower ends of which rods rest upon, and may be attached to,the upper steel plate, while their upper ends pass into, and slidewithin, holes made to receive them in the side piece A, of the mainframe. The spiral springs are not in a state of tension when there is noload upon them but that of the car, or other vehicle, to which they areapplied; nor do they, in fact, extend from the steel plate so as to comeinto contact with the under side of the frame, but terminate atdifferent distances therefrom, so that the respective pairs aresuccessively brought into action, as the steel spring is straightened bythe action of the load. The two outer spirals may, for example, extendup to within half an inch of the bottom of the frame, the next pair towithin an inch, and the next to within an inch and a half, more or less,according to circumstances. By this arrangement, the respective pairswill be brought into action accordingly as the load is increased, and atthe same time each of the springs will continue to operate as a spring,which is not the case, or is so to a small extent only, in springs ofother constructions, in which it has been attempted to graduate theiraction to the load.

In the second modification of my spring, represented in the drawing, B,B, is a steel spring similar to that above described, and it isrepresented as hung upon scrolled ends in the same way.

E, E, is the lower part of the frame of a car body, or other vehicle,between which and the main frame A, A, the spiral springs D, D, D, aresituated, said springs being coiled around the rods F, F, F; the lowerends of which rest upon the steel spring, while said rods slide freelywithin holes made through the pieces A, and E, for that purpose. Thesesprings are graduated so as to be brought successively into action,according to the weight of the load, in the manner already described. Ihave represented six spiral springs in eachcombination, but this numbermay be varied at pleasure.

Having thus, fully described the nature of my invention, and shown themanner in which the same is carried into practical operation, what Iclaim therein, and desire to secure by Letters Patent, is,

The manner in which I have combined the steel plate spring, asconstructed with scrolled ends, or with the ends attached to vibratingbars, or to be received into pockets, with the spirial springs, whichare so gradu ated in length as to be successively brought into actionaccording to the bearing of the load, as herein described.

WVILLIAM- DUFF.-

Witnesses:

THOMAS R. SCOTT, J OHN BROWN.

